WIP: Support 'export' in triggers file to set env variables
This is a prerequisite to be able to test against the FIPS provider in OpenSSL 3.0.0
Note that it is not sufficient to set the variable in the environment of the triggerflow parent process as this does not affect the gdb
process which is forked before the triggers file is parsed.
It's WIP because while the new unit tests are passing here, using it in openssl-triggerflow-ci
is currently causing exceptions in the gdb-ruby
layer.